1. Field of the Invention
The present invention relates to a wood member for a musical instrument, such as a key, a keyframe, or a hammer shank for use e.g. in a piano, and a method of manufacturing the wood member, as well as a soundboard manufacturing system and method for manufacturing a wooden soundboard for use in an acoustic musical instrument, such as a piano, a violin, or a guitar.
2. Description of the Related Art
Conventionally, there have been known a wood member for a musical instrument (hereinafter simply referred to as “the wood member”) and a wood member manufacturing method, which are disclosed e.g. in Japanese Patent No. 3562517. According to the wood member manufacturing method, an unmachined or machined wood workpiece as a workpiece for the wood member (hereinafter simply referred to as “the wood workpiece”) is left standing in an autoclave filled with high-pressure steam at a temperature of 120 to 200° C. and a pressure of 0.2 to 1.6 MPa for 1 to 60 minutes, whereby the wood member is manufactured. The wood workpiece has properties thereof modified by the high-pressure steam treatment and is deeply hued, whereby a unique texture and a deep feel which cannot be expected a wood member unsubjected to the high-pressure steam treatment are obtained, and a coating process is shortened.
The above-described manufacturing method is applied to a soundboard manufacturing method as well. In this case, a soundboard workpiece as a workpiece for a soundboard has its properties modified by the high-pressure steam treatment. As a consequence, an increase in the Young's modulus of the soundboard workpiece, reduction of loss tangent, reduction of density, etc. are achieved, and the acoustic conversion efficiency of the soundboard is increased, whereby a soundboard is obtained which is excellent in vibration characteristics i.e. acoustic characteristics.
In general, the wood member is apt to suffer from damage, such as cracking, which is caused by growth of a fine flaw in an outer peripheral portion thereof due to tensile stress. In the meanwhile, in the case of the conventional wood member, the wood workpiece has its properties modified only by the high-pressure steam treatment, and hence it is impossible to prevent damage to the wood member due to the above-mentioned factor. Therefore, there is a fear that occurrence of damage adversely affects the operation of the musical instrument or the appearance of the same.
Further, in the above-described soundboard manufacturing method, in which the soundboard workpiece is only left standing in high-pressure steam at a predetermined temperature and a predetermined pressure over a predetermined time period, it is only possible to perform the overall temperature adjustment of the soundboard workpiece, but it is impossible to control the actual temperature of the soundboard workpiece in a fine-grained manner. For this reason, the actual temperature of the soundboard workpiece cannot be controlled to an appropriate temperature, and therefore it is impossible to obtain a soundboard workpiece whose properties are accurately modified by heating. Furthermore, internal strain is apt to remain in the manufactured soundboard, which makes internal friction in the soundboard relatively high. Therefore, there is a fear that the internal friction degrades the acoustic characteristics of the soundboard.